symfony - Ratchet Web 套接字请求中的连接 ID

Question

我正在用 Symfony 测试 Ratchet。测试很好，但我无法理解属性$conn->resourceID的来源......这是官方教程中的代码

<?php
namespace MyApp;
use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
class Chat implements MessageComponentInterface {
    protected $clients;
    public function __construct() {
        $this->clients = new \SplObjectStorage;
    }
    public function onOpen(ConnectionInterface $conn) {
        // Store the new connection to send messages to later
        $this->clients->attach($conn);
        echo "New connection! ({$conn->resourceId})\n";
    }
    public function onMessage(ConnectionInterface $from, $msg) {
        $numRecv = count($this->clients) - 1;
        echo sprintf('Connection %d sending message "%s" to %d other connection%s' . "\n"
            , $from->resourceId, $msg, $numRecv, $numRecv == 1 ? '' : 's');
        foreach ($this->clients as $client) {
            if ($from !== $client) {
                // The sender is not the receiver, send to each client connected
                $client->send($msg);
            }
        }
    }
    public function onClose(ConnectionInterface $conn) {
        // The connection is closed, remove it, as we can no longer send it messages
        $this->clients->detach($conn);
        echo "Connection {$conn->resourceId} has disconnected\n";
    }
    public function onError(ConnectionInterface $conn, \Exception $e) {
        echo "An error has occurred: {$e->getMessage()}\n";
        $conn->close();
    }
}

我找不到它（$conn->resourceID），IDE 找不到它，但它可以工作，它以某种方式填充......

有没有人有线索可以帮助我理解？

谢谢